(1) Field of the Invention
The present invention generally relates to electrical grounding equipment, and more particularly, to a shield ground adapter ("SGA" hereinafter) and to a conduit ground adapter ("CGA" hereinafter) designed to shunt high level electromagnetic ("EM" hereafter) energy from cable shields or conduits to a metallic boundary or ground plane such as a kickpipe/stuffing tube ("KP/ST" hereinafter) assembly, through which the cable passes. The EM energy can be caused by lightning, or by such high level EM sources as an electromagnetic pulse ("EMP" hereinafter). This shunting of EM energy from the cable shield or conduit to the metallic boundary, through which the cable passes, prevents the high level currents, voltages and EM fields induced thereby, from penetrating into the space protected by the metallic boundary or ground plane, through which the cable passes.
(2) Description of the Prior Art
Prior to the present invention all ground adapters, SGA's and CGA's utilized either soldered, compression or spring type devices to electrically connect the shield or conduit to a mechanical adapter assembly. Such assemblies were then threaded into KP/ST assemblies to provide mechanical connection to the ground plane or metallic boundary. The electrical connection to the ground plane or metallic boundary was provided by either mechanical threads, or by a spring type device, which typically required that the cable, conduit or KP/ST assembly meet stringent dimensional tolerances. Electrical connection to the KP/ST assemblies were typically made using the inside threads of the KP/ST. These thread interfaces have been shown to degrade over time and environmental conditions until the EMI/EMP ground is completely lost. With all of these heretofore known devices, the size of the ground adapter that was used was dependent on both the cable or conduit size and on the KP/ST size, which required a stock of separate ground adapters for every different cable/conduit and ST/KP assembly size combination. If, for example, ten different sizes of cable or conduit and five different sizes of KP/ST assemblies were required, an inventory of as many as fifty differently sized ground adapters had to have been stocked. Furthermore, cable conduits and KP/ST assemblies that were to be nominally of the same size but were manufactured by different companies have nonetheless had different dimensions. In order to accommodate such dimensional differences, a stock of a set of ground adapters for each manufacturer had to have been maintained. These heretofore known ground adapter devices suffered from the further limitation that no ground adapter was completely cross-compatible, as, for example, an adapter designed for grounding shields was not compatible for use with a conduit, and vice versa.